(a) Field of the Invention
The present invention relates to a scrambling system and method in MC-CDMA (multicarrier code-division multiple access), and a recording medium for storing its program. More specifically, the present invention relates to a scrambling system and method in MC-CDMA for reducing PAPR (peak-to-average power ratio) and improving link performance.
(b) Description of the Related Art
In the first prior art, methods for reducing the PAPR include a PTS (partial transmit sequence) method used for OFDM (orthogonal frequency division multiplexing), which is a non-spreading multicarrier system, and a method for applying the SM (selective mapping) method to the MC-CDMA system.
The methods according to first prior art reduce the PAPR, but they further require an individual operation for reducing the PAPR for each transmission symbol, and transmit corresponding additional information to a receiver.
In the second prior art, the methods for reducing the PAPR in the MC-CDMA system include a method for allowing a transmitter and a receiver to selectively use a user's orthogonal code and reduce a mean power in a MC-CDMA system that performs no scrambling process.
The second prior art is applied to systems that do not perform the scrambling, but most of the CDMA systems use scramble codes.
In general, the system that performs scrambling reduces the PAPR further than the system that does not perform scrambling, irrespective of the user's code combination.
Therefore, the second prior art fails to acquire practical effects of PAPR reduction in the case of the system that performs scrambling.